textproduct: Quad Cities

KEY MESSAGES

- Extreme Heat Warning continues through Wednesday evening due to a prolonged period of hot and very humid conditions. Daily peak heat index values of 100 to 110 and nighttime low temperatures only dropping into the mid 70s.

- Increasing thunderstorm chances into midweek onward (including the July 4th weekend), with the resultant cloud cover potentially having an impact on high temperatures. Very humid conditions will remain.

SHORT TERM /THROUGH TUESDAY NIGHT/

Issued at 230 PM CDT Mon Jun 29 2026

Upper ridge to continue across the central and southeastern US with southwesterly flow across the Plains into the Great Lakes. This pattern continues to allow the heat to build across the area with very humid conditions as well with flow off the Gulf. Heat index values already into 100-105 range or higher at many sites today, and even warmer air aloft expected to push into the area Tuesday. Little relief expected at night with the humid airmass and warm temperatures keeping overnight temperatures dropping into the upper 70s to around 80. The Extreme Heat Warning will continue with the heat expected through midweek.

LONG TERM /WEDNESDAY THROUGH MONDAY/

Issued at 230 PM CDT Mon Jun 29 2026

The upper ridge across the central/southern US to begin to break down some into the middle to end of the week allowing the southwesterly flow aloft to become oriented more across the forecast area. This will bring increasing chances for thunderstorms by Wednesday into the weekend, especially into the weekend as the ridge breaks down further with a more zonal flow pattern setting up with stronger shortwave troughs impacting the region. Therefore the continuation of the heat and high temperatures into the end of the week and this weekend are somewhat uncertain dependent on thunderstorm chances due to cloud cover and overall storm chances, etc. Continued moisture flow off the Gulf remains, so humid conditions will continue through the forecast period. For now the threat of strong to severe storms is still uncertain for any one period, however the pattern would suggest more organization with the storm chances into the weekend with the stronger upper level troughs helping force the storm chances.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 615 PM CDT Mon Jun 29 2026

Southerly winds will be the main factor in all sites through Tuesday, as high pressure remains in control of our weather locally. Skies may see some additional cumulus tomorrow, but with hotter air over the region, this should be higher based and less widespread than today's diurnal cumulus, which is breaking up at this time, and by 00z, skies will be mainly clearing.

Winds Tuesday will shift more towards southwest during the day, with gusts to the 20-25 kt range much like today, albeit a little bit lower.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Extreme Heat Warning until 10 PM CDT Wednesday for IAZ040>042- 051>054-063>068-076>078-087>089-098-099. IL...Extreme Heat Warning until 10 PM CDT Wednesday for ILZ001-002- 007-009-015>018-024>026-034-035. MO...Extreme Heat Warning until 10 PM CDT Wednesday for MOZ009-010.